Rigid Capacitive Sensor Structure for Redundant Robot Proximity Detection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing capacitive sensors for area detection of object approach lack robustness and ease of attachment to mechanical components, particularly in mechatronic systems and robots, and do not provide reliable redundant detection.

Innovation Solution

A capacitive sensor design featuring a rigid and torsionally rigid structure with a circuit carrier, spacer element, and conductive surfaces arranged to form overlapping capacitances, allowing for early detection of object approach without physical contact and enabling redundant monitoring, which is cost-effective and easy to attach and replace.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If capacitive sensors are made flexible and attachable like a jacket, then ease of attachment is improved, but structural stability and rigidity deteriorate

Engineering Contradiction:
Improveease of attachmentVSAvoidstructural stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The capacitive sensor is divided into multiple individual sensor elements that can be independently attached to the machine part. Each sensor element is small and flexible, but collectively they provide comprehensive coverage. This segmentation allows easy attachment of individual elements while maintaining overall system stability through their distributed arrangement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensor elements utilize flexible printed circuit boards as their substrate, allowing them to conform to curved surfaces and be easily attached like a jacket over machine parts. The flexible nature of the thin film substrate enables easy installation while the rigid circuit carrier within each element maintains structural stability during operation.

Inventive Principle:
Principle #30Flexible shells and thin films

2Stability of the object's composition

If capacitive sensors are made large and rigid, then structural stability is improved, but ease of attachment and replacement deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidease of attachment
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The sensor system is segmented into multiple small, standardized sensor elements rather than one large sensor. Each small element can be easily handled, attached, and replaced individually, while collectively providing the necessary coverage area. This segmentation resolves the contradiction between size/rigidity and ease of attachment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensor elements are designed with universal mounting features and standardized dimensions, allowing them to be attached to various machine parts using the same method. This universality enables easy attachment and replacement across different applications without requiring custom solutions for each size or shape.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Area of stationary object

If multiple capacitive sensor elements are lined up to form a sensor skin, then area detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvedetection areaVSAvoidsensor system complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

Multiple sensor elements are merged into a coordinated system where each element performs the same detection function independently. The evaluation unit processes signals from all elements using a unified algorithm, detecting approaches in the overall area by combining information from individual elements. This merging approach expands detection area while managing complexity through standardized processing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses multiple sensor elements providing redundant detection coverage, where each element monitors a portion of the total area. This partial action approach allows the system to detect approaches reliably across the entire area by having multiple overlapping detection zones, improving reliability without requiring complex coordination between elements.

Inventive Principle:
Principle #16Partial or excessive action

4Adaptability or versatility

If capacitive sensors lack rigid structure, then flexibility and ease of mounting is improved, but reliability and robustness against environmental influences deteriorates

Engineering Contradiction:
ImproveflexibilityVSAvoidrobustness
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The sensor elements use flexible printed circuit board substrates that provide the necessary flexibility for mounting on various machine parts. These thin film structures can conform to curved surfaces and are easy to install, while the rigid circuit carrier within each element provides structural stability and reliability during operation.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

Each sensor element combines multiple materials with complementary properties: a flexible substrate for adaptability, a rigid circuit carrier for structural stability, and conductive layers for sensing functionality. This composite structure integrates both flexibility and robustness, allowing the sensor to adapt to different mounting surfaces while maintaining reliable operation under environmental influences.

Inventive Principle:
Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The capacitive sensor effectively detects object approach early and reliably, even in complex environments, ensuring safe operation of robots and machine parts by providing redundant detection capabilities and withstanding environmental influences, while being cost-effective and easy to integrate.

Implementation Method 1

two mutually adjacent electrically conductive surfaces which are insulated from one another and which form an electrical capacitance in such a way that the value of the capacitance changes when an object approaches

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

After the capacitance has been charged, an electric field forms in the form of electric field lines between the electrically conductive surfaces in the space between the electrically conductive surfaces. When an object approaches, this electric field is disturbed

Methodology Applied
Scientific EffectElectric Field: Electric Field

Data Source

PatentEP3194831B1Capacitive sensor
Publication Date: 2022.02.16 ROBERT BOSCH GMBH
  • EP3194831B1 patent drawingFigure 1~2
  • EP3194831B1 patent drawingFigure 3~4
  • EP3194831B1 patent drawingFigure 5~6

AI summary

The invention relates to a capacitive sensor for identifying at a surface that an object is approaching, wherein the capacitive sensor is of flexurally rigid and/or torsionally rigid design. The capacitive sensor preferably comprises a circuit carrier and/or a spacer element and/or a carrier. In this case, the circuit carrier is of flexurally rigid and/or torsionally rigid design and/or the spacer element is of flexurally rigid and/or torsionally rigid design and/or the carrier is of flexurally rigid and/or torsionally rigid design. The circuit carrier is preferably in the form of a printed circuit board and serves to make electrical contact with the electrically conductive surfaces of the capacitive sensor. The spacer element is arranged between the electrically conductive surfaces and the circuit carrier. The carrier is designed to connect the capacitive sensor to a machine part, in particular to a machine part of an industrial robot 